Reliability measures for buried flexible pipes

2005 ◽  
Vol 42 (2) ◽  
pp. 541-549 ◽  
Author(s):  
G L Sivakumar Babu ◽  
Rajaparthy S Rao
Keyword(s):  
Bulk Density ◽  
Primary Objective ◽  
Design Parameters ◽  
Reliability Measures ◽  
Buried Pipe ◽  
Cross Sectional ◽  
Flexible Pipes ◽  
Safety And Reliability ◽  
Soil Modulus ◽  
Testing Design

The safety of infrastructure facilities such as buried pipelines is the primary objective of engineering design. An improved measure of safety and reliability of these structures can be obtained with concepts of probability. The assessment of safety involves uncertainties at various stages, such as testing, design, and field installation and operations. This paper presents a reliability analysis to estimate the deflection (cross-sectional ovalization) and buckling response of buried flexible pipes, considering uncertainties in the design parameters. The need to consider variations in design parameters, such as soil modulus and bulk density of the fill, and the influence of correlation between soil modulus and bulk density in the estimation of reliability is emphasized. It was observed that reliability index decreases with an increase in the coefficient of variation of soil modulus and bulk density of the fill and increases with increase in correlation coefficient between the variables. It is possible to obtain a central factor of safety (CFS) value on the basis of the target reliability and variations in the design parameters. The use of reliability-based considerations is illustrated with two typical simple cases of buried pipe installations.Key words: reliability measures, buried flexible pipes, deflection (ovalization), buckling, variability, safety.

scholarly journals Use of Ceftaroline in Hospitalized Patients with and without COVID-19: A Descriptive Cross-Sectional Study

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 763
Author(s):  
Daniele Roberto Giacobbe ◽  
Chiara Russo ◽  
Veronica Martini ◽  
Silvia Dettori ◽  
Federica Briano ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Bloodstream Infections ◽  
Cross Sectional Study ◽  
Primary Objective ◽  
Sectional Study ◽  
Cross Sectional ◽  
First Line Therapy ◽  
Large Teaching Hospital ◽  
Secondary Objective ◽  
Medical Wards

A single-center cross-sectional study was conducted to describe the use of ceftaroline in a large teaching hospital in Northern Italy, during a period also including the first months of the coronavirus disease 2019 (COVID-19) pandemic. The primary objective was to describe the use of ceftaroline in terms of indications and characteristics of patients. A secondary objective was to describe the rate of favorable clinical response in patients with bloodstream infections (BSI) due to methicillin-resistant Staphylococcus aureus (MRSA-BSI) receiving ceftaroline. Overall, 200 patients were included in the study. Most of them had COVID-19 (83%, 165/200) and were hospitalized in medical wards (78%, 155/200). Included patients with COVID-19 pneumonia were given empirical ceftaroline in the suspicion of bacterial co-infection or superinfection. Among patients with MRSA-BSI, ceftaroline was used as a first-line therapy and salvage therapy in 25% (3/12) and 75% (9/12) of cases, respectively, and as a monotherapy or in combination with daptomycin in 58% (7/12) and 42% (5/12) of patients, respectively. A favorable response was registered in 67% (8/12) of patients. Improving etiological diagnosis of bacterial infections is essential to optimize the use of ceftaroline in COVID-19 patients. The use of ceftaroline for MRSA-BSI, either as a monotherapy or in combination with other anti-MRSA agents, showed promising rates of favorable response.

scholarly journals Research on the Computed Tomography Pebble Flow Detecting System for HTR-PM

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Xin Wan ◽  
Ximing Liu ◽  
Jichen Miao ◽  
Peng Cong ◽  
Yuai Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Helical Ct ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Safe Operation ◽  
Cross Sectional ◽  
Ct System ◽  
Near Future ◽  
Pebble Flow

Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.

scholarly journals Vacuum Dynamics as an Alternative Method for Detection of Bimodal Milk Ejection in Dairy Cows

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1860
Author(s):  
Matthias Wieland ◽  
Christina Marie Geary ◽  
Gloria Gioia ◽  
Kerry Lynn Case ◽  
Paolo Moroni ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Predictive Value ◽  
Primary Objective ◽  
Cow Milk ◽  
Kappa Statistics ◽  
Flow Meter ◽  
Flow Curves ◽  
Cross Sectional ◽  
Gold Standard Method ◽  
Milk Flow

The primary objective of our study was to assess the ability of a vacuum recorder to detect the presence of bimodal milk flow curves in dairy cows compared with a portable milk flow meter. In a cross-sectional study, 241 individual cow milking observations were analyzed. We simultaneously collected (1) individual cow vacuum events during milking using portable vacuum recorders, and (2) individual cow milk flow curves by attaching a portable milk flow meter to the same milking unit. Presence of bimodality was assessed with the vacuum recorder visually (BIMVA) and with the gold standard method of a milk flow meter through automatic detection (BIMLA). Kappa statistics revealed moderate agreement between BIMVA and BIMLA [κ, 95% confidence intervals (95% CI) = 0.59 (0.46–0.71)]. Diagnostic test statistics for BIMVA for detection of bimodality indicated moderate performance for sensitivity [0.65 (0.52–0.76)] and positive predictive value [0.71 (0.58–0.82)] and high values for specificity [0.92 (0.87–0.95)] and negative predictive value [0.93 (0.84–0.93)]. We conclude that milking vacuum dynamics are a suitable measure to assess bimodal milk flow curves in dairy cows.

scholarly journals P55 FutureCOVID: Exploring the perspectives of doctors & nurses of student response during the COVID-19 pandemic

BJS Open ◽  
2021 ◽  
Vol 5 (Supplement_1) ◽  
Author(s):  
◽  
Vigneshwar Raj Veerappan ◽  
Michal Kawka ◽  
Aleksander Dawidziuk ◽  
Sanskrithi Sravanam ◽  
...  
Keyword(s):  
Medical Students ◽  
Quantitative Methods ◽  
Primary Objective ◽  
Student Response ◽  
Healthcare Staff ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Qualitative And Quantitative Methods ◽  
Training Adaptations ◽  
Healthcare Settings

Abstract Introduction The training medical students receive means they can be used as auxiliary healthcare staff during pandemics and disasters. During COVID-10, many medical students volunteered in healthcare settings in clinical and non-clinical capacities. While there has been research into students’ perceptions of the pandemic and their role within the NHS, the perceptions of healthcare staff perceive this student response has not been explored. Methods COVIDAssist is a survey based cross sectional observational study of medical student volunteering during COVID-19. The study consists of a cross sectional survey of doctors & nurses who worked alongside medical students in the NHS during the pandemic. We will use qualitative and quantitative methods to analyze responses. Results The primary objective of the study is to assess how effective student response was in reducing the burden on healthcare teams during the pandemic. Secondary objectives are: to identify the broad specialty (e.g. medicine, surgery, primary care) and healthcare roles medical students were most beneficial) ; the GMC outcome-based skills students exhibited; the training provided to students before volunteering and what additional training could have been provided to students. Conclusion The outcomes of this study will help inform current and future guidance on effective student deployment during pandemics and disasters. The results are also expected to provide insight into necessary training adaptations.

scholarly journals Design of an Ultra-Wideband Microstrip-to-Slotline Transition on Low-Permittivity Substrate

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1329
Author(s):  
Jung Seok Lee ◽  
Gwan Hui Lee ◽  
Wahab Mohyuddin ◽  
Hyun Chul Choi ◽  
Kang Wook Kim
Keyword(s):  
Microstrip Line ◽  
Return Loss ◽  
Analytical Formula ◽  
Parameter Tuning ◽  
Ultra Wideband ◽  
Design Parameters ◽  
Analytical Line ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Low Permittivity

Analysis and design of an ultra-wideband microstrip-to-slotline transition on a low permittivity substrate is presented. Cross-sectional structures along the proposed transition are analyzed using conformal mapping assuming quasi-TEM modes, attaining one analytical line impedance formula with varying design parameters. Although the slotline is a non-TEM transmission line, the transitional structures are configured to have quasi-TEM modes before forming into the slotline. The line impedance is optimally tapered using the Klopfenstein taper, and the electric field shapes are smoothly transformed from microstrip line to slotline. The analytical formula is accurate within 5% difference, and the final transition configuration can be designed without parameter tuning. The implemented microstrip-to-slotline transition possesses insertion loss of less than 1.5 dB per transition and return loss of more than 10 dB from 4.4 to over 40 GHz.

Effect of Design Parameters on Drop Test Performance of Wafer Level Chip Scale Packages (WLCSP)

2011 ◽  
Author(s):  
Pushkraj Tumne ◽  
Vikram Venkatadri ◽  
Santosh Kudtarkar ◽  
Michael Delaus ◽  
Daryl Santos ◽  
...  
Keyword(s):  
Flip Chip ◽  
Bulk Solder ◽  
Consumer Electronics ◽  
Drop Test ◽  
Design Parameters ◽  
Mechanical Shock ◽  
Wafer Level ◽  
Cross Sectional ◽  
Right Censored Data ◽  
Solder Balls

Today’s consumer market demands electronics that are smaller, faster and cheaper. To cater to these demands, novel materials, new designs, and new packaging technologies are introduced frequently. Wafer Level Chip Scale Package (WLCSP) is one of the emerging package technologies that have the key advantages of reduced cost and smaller footprint. The portable consumer electronics are frequently dropped; hence the emphasis of reliability is shifting towards study of effects of mechanical shock loading increasingly. Mechanical loading typically induces brittle fractures (also known as intermetallic failures) between the solder bumps and bond pads at the silicon die side. This type of failure mechanism is typically characterized by the board level drop test. WLCSP is a variant of the flip-chip interconnection technique. In WLCSPs, the active side of the die is inverted and connected to the PCB by solder balls. The size of these solder balls is typically large enough (300μm pre-reflow for 0.5mm pitch and 250μm pre-reflow for 0.4mm pitch) to avoid use of underfill that is required for the flip-chip interconnects. Several variations are incorporated in the package design parameters to meet the performance, reliability, and footprint requirements of the package assembly. The design parameters investigated in this effort are solder ball compositions with different Silver (Ag) content, backside lamination with different thickness, WLCSP type –Direct and Re-Distribution Layer (RDL), bond pad thickness, and sputtered versus electroplated Under Bump Metallurgy (UBM) deposition methods for 8×8, 9×9, and 10×10 array sizes. The test vehicles built using these design parameters were drop tested using JEDEC recommended test boards and conditions as per JESD22-B11. Cross sectional analysis was used to identify, confirm, and classify the intermetallic, and bulk solder failures. The objective of this research was to quantify the effects and interactions of WLCSP design parameters through drop test. The drop test data was collected and treated as a right censored data. Further, it was analyzed by fitting empirical distributions using the grouped and un-grouped data approach. Data analysis showed that design parameters had a significant effect on the drop performance and played a vital role in influencing the package reliability.

Numerical Investigation of the Effect of Diffuser and Volute Design Parameters on the Performance of a Centrifugal Compressor Stage

2016 ◽  
Author(s):  
Lei Yu ◽  
William T. Cousins ◽  
Feng Shen ◽  
Georgi Kalitzin ◽  
Vishnu Sishtla ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Gas Flow ◽  
Pressure Rise ◽  
Design Parameters ◽  
Compressor Stage ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Centrifugal Stage ◽  
And Performance ◽  
The Impact

In this effort, 3D CFD simulations are carried out for real gas flow in a refrigeration centrifugal compressor. Both commercial and the in-house CFD codes are used for steady and unsteady simulations, respectively. The impact on the compressor performance with various volute designs and diffuser modifications are investigated with steady simulations and the analysis is focused on both the diffuser and the volute loss, in addition to the flow distortion at impeller exit. The influence of the tongue, scroll diffusion ratio, diffuser length, and cross sectional area distribution is examined to determine the impact on size and performance. The comparisons of total pressure loss, static pressure recovery, through flow velocity, and the secondary flow patterns for different volute designs show that the performance of the centrifugal compressor depends upon how well the scroll portion of the volute collects the flow from the impeller and achieves the required pressure rise with minimum flow losses in the overall diffusion process. Finally, the best design is selected based on compressor stage pressure rise and peak efficiency improvement. An unsteady simulation of the full wheel compressor stage was carried out to further examine the interaction of impeller, diffuser and the volute. The unsteady flow interactions are shown to have a major impact on the performance of the centrifugal stage.

scholarly journals FREQUENCY OF FUNCTIONAL DISABILITY AND COGNITIVE IMPAIRMENTS IN SUB-ACUTE STROKE PATIENTS

2021 ◽  
Vol 10 (2) ◽  
pp. 69-74
Author(s):  
Aisha Sarfaraz ◽  
Dr Abdul Azeem ◽  
Mehwish Butt ◽  
Muhammad Umar
Keyword(s):  
Acute Stroke ◽  
Functional Disability ◽  
Cognitive Impairments ◽  
Age Groups ◽  
Female Gender ◽  
Primary Objective ◽  
P Value ◽  
Stroke Patients ◽  
Cross Sectional Survey ◽  
Cross Sectional

BACKGROUND & OBJECTIVE Stroke is a very common neurological condition affects various aspects of health. The primary objective of this study was to find out the frequency of functional disability and cognitive impairments in Sub-acute Stroke patients. MATERIAL AND METHODS A cross-sectional survey was conducted on 112 Sub-acute Stroke patients in Karachi, Pakistan. Using Barthel Index (BI) and Mini-Mental State Examination (MMSE) test was used to find out the frequency of functional disability and cognitive impairments of Sub-acute Stroke patients. RESULTS The correlation of BI scores with MMSE scores for the Male gender was 0.576 whilst the correlation of BI scores with MMSE scores for the Female gender was 0.440. The severity of functional disability concerning age groups assessed P-value was 0.026 using Chi-Square Test. The severity of functional disability (BI severity) concerning gender, P-value was found 0.097 using the same test. CONCLUSION Functional Disability is directly linked with age. However, there was no linkage established between Cognitive Impairment and age as well as gender. On close inspection, there was a trend between Functional disability and gender but not statistically significant.

scholarly journals Late stage presentation of HIV-positive patients to antiretroviral outpatient clinic in Zambia

2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Timothy Martin ◽  
Morgan Mweene
Keyword(s):  
Clinical Stage ◽  
Primary Objective ◽  
World Health ◽  
Stage Iii ◽  
Clinical Staging ◽  
Hiv Positive ◽  
Eligibility Criteria ◽  
Design Data ◽  
Cross Sectional ◽  
Clinical Records

Background: The World Health Organization (WHO) and the Zambian Ministry of Health set out new guidelines on combination antiretroviral therapy (cART) in 2013 expanding the eligibility criteria for patients with HIV.Objectives: The primary objective were to determine when cART was initiated in HIV-positive outpatients according to clinical and immunological criteria, and to identify what proportion of patients who were eligible for cART according to 2013 WHO and 2013 Zambian cART guidelines were currently on cART.Methodology: This was a clinical audit of HIV-positive outpatients attending the cART clinic at Ndola Central Hospital in Ndola, Zambia, with retrospective cross-sectional chart review and survey design. Data were collected from clinical records and interviews with patients.Results: A total of 99% of patients eligible for cART according to 2013 guidelines were on treatment. Clinical staging of patients at initiated on cART (n = 206) was as follows: 28% clinical stage I, 21% clinical stage II, 36% clinical stage III and 15% clinical stage IV. The median CD4 count when patients were started on cART was 147 cells/mm3 .Conclusion: The results show that a majority of patients were initiated on cART late in their disease course according to immunological (CD4 < 200 cell/mm3 ) and clinical criteria (stage III or IV). However, the vast majority of patients eligible for cART were currently on treatment. The late initiation of cART appears to be a result of late diagnosis of HIV.

scholarly journals EVALUATION OF THE EFFECT OF CORONAVIRUS PANDEMIC ON SUPPLY CHAIN OF HIV TEST KITS ONDO STATE, SOUTHWEST NIGERIA

2021 ◽  
Vol 6 (9) ◽  
pp. 34-78
Author(s):  
Michael Olabode Tomori ◽  
Funmilayo Adenike Fadiji
Keyword(s):  
Supply Chain ◽  
Data Analysis ◽  
Communicable Disease ◽  
Primary Objective ◽  
Health Facilities ◽  
Least Square ◽  
National Guidelines ◽  
Cross Sectional ◽  
Hiv Test ◽  
Ondo State

COVID-19 pandemic has required swift revamping of health systems and public health measures at a scale never observed. The pandemic emergence has a direct effect on the health system, negatively affecting its capacity as depletion of resources are now channelled to curb the emergency of the communicable disease, especially among individuals living with HIV disease which drew our attention to how individuals suffering from HIV and people who needed to know their HIV status has not been able to visit the health facilities due to the effect of coronavirus pandemic on the supply of the test kits used in the health facilities. This study evaluated the effect of the coronavirus pandemic on the supply chain of HIV test kits in Ondo State, Nigeria. The primary objective was to determine the effect of the coronavirus pandemic on the supply of HIV test kits in Ondo State. The research was a sequential cross-sectional design using a quantitative method of analysis with a total sample size of 100 respondents with all samples drawn from 30 supported health facilities in the state. In addition, literature review was also used to know the effect of the coronavirus on reach of 95% of UNAIDS 2030 target. The study used both descriptive and inferential methods of data analysis where the descriptive statistics comprise of frequency distribution, percentage distribution, weighted mean score, and standard deviation while the inferential method of data analysis used ordinal least square (simple linear regression) to determine the effect of coronavirus pandemic on the supply chain test kits. Findings from the result concluded that pandemic and the methods of supply chain management indicated a significant effect. In addition, from the review the major impacts of COVID-19 were innovation, increased technology, research and development, depletion of supply chain personnel. Therefore, there is a need to develop national guidelines on supply chain strategy for emergencies in Nigeria as well as adhere strictly to some recommendations made in the study.

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